Overview - Piston And Connecting Rod

Fig 1: Overview Of Piston And Connecting Rod

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1. Bolts
   • 30 Nm + 90° turn
   • Replace
   • Lubricate the thread and contact surface.
   • Use old bolts to measure radial play.
2. Connecting Rod Bearing Cap
   • Mark for installation later.
   • Mark allocation to the cylinder with paint -B-. Refer to Fig 7.
   • Note when installing the bearing cap: the wide thrust flange -A- must point to the same side on connecting rod and connecting rod bearing cap.
   • Installation position of connecting rod pairs. Refer to Fig 8.
3. Bearing Shell
   • Make sure the tabs are tight
   • Mark used bearing shells for reinstallation but not on the running surface
   • Replace the bearing shells worn down to the base layer
4. Connecting Rod
   • Always replace as a set.
   • Mark allocation to the cylinder with paint -B-. Refer to Fig 7.
   • Note when installing the bearing cap: the wide thrust flange -A- must point to the same side on connecting rod and connecting rod bearing cap
   • Installation position of connecting rod pairs. Refer to Fig 8
   • Radial play, measuring. Refer to CONNECTING RODS, CHECKING RADIAL CLEARANCE .
5. Piston Pin
   • Heat piston to 60 °C if it is difficult to move.
   • Remove and install using the Pilot Drift VW222A
6. Circlip
   • Replace
7. Piston
   • Mark the installation position and cylinder allocation. Refer to Fig 6.
   • Arrow on piston face points toward belt pulley side.
   • Checking. Refer to Fig 4.
   • Replace the piston if there are cracks on the piston head or piston shaft.
   • Install with piston ring compressor.
   • Piston and Cylinder Dimensions. Refer to PISTON AND CYLINDER DIMENSIONS .
   • Measuring cylinder bore. Refer to Fig 5.
8. Piston Rings
   • Offset gaps by 120°
   • Use piston ring pliers for removing and installing
   • Installed position: "TOP" marking or side with writing faces the piston crown.
   • Measuring the gap. Refer to Fig 2
   • Measuring side clearance. Refer to Fig 3

Fig 2: Checking Piston Ring Gap

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-- Push the piston ring squarely from above down to approximately 15 mm from the bottom end of the cylinder.

-- Use a piston without a piston ring for sliding in.

Fig 3: Checking Piston Ring Groove Clearance

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-- Clean the piston ring groove before checking.

Fig 4: Checking Pistons For Deviation

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-- Measure approximately 15 mm from the lower edge at a 90° angle to the piston pin axis using a 75 to 100 mm external micrometer.

• Maximum deviation from nominal dimension: 0.04 mm.

Nominal dimension. Refer to PISTON AND CYLINDER DIMENSIONS .

Fig 5: Checking Cylinder Bores

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-- Using the Cylinder Dial Bore Gauge VAS6078 measure in a diagonal sequence at three positions transversely -A- and longitudinally -B-.

• Maximum deviation from the specified dimension: 0.08 mm.

Nominal dimension. Refer to PISTON AND CYLINDER DIMENSIONS .

Fig 6: Identifying Installed Position Of Piston And Piston/Cylinder Allocation

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Installed position:

• The arrows on the piston heads point to the belt pulley side.

Fig 7: Arrows On Piston Heads Point To Belt Pulley Side

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-- Mark the connecting rod and connector rod bearing caps to each other and to the cylinder -arrow- with paint for installation.

Fig 8: Marking Connecting Rod And Connector Rod Bearing Caps To Each Other And To Cylinder Location

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• The molded tabs -arrows- on the beveled surfaces of the connecting rod pairs "1 and 2", "3 and 4" and "5 and 6" must face each other.

Fig 9: Identifying Oil Spray Jet And Bolt

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1. Insert the bolt with locking compound and tighten to 9 Nm. For the correct locking compound.
2. Oil spray jet with spray nozzle valve (opening pressure 2 to 2.4 bar)